Closure device for a vessel holding an operating medium

ABSTRACT

A closure device for a vessel for holding an operating medium includes a tank closure ( 2 ) and a tank stub ( 1 ). The tank stub ( 1 ) defines a fill opening having a sealing surface ( 16 ) disposed therearound. The tank closure ( 2 ) includes an outer part ( 6 ) and an inner part ( 8 ) which are limitedly movable toward one another in the axial direction of the tank stub ( 1 ). The inner part ( 8 ) does not rotate but is guided axially displaceably in the tank stub ( 1 ) and the outer part ( 6 ) is rotatable relative to the inner part ( 8 ) on the tank stub ( 1 ) so as to be fix-tightly screwable thereon. A spring ( 26 ) is provided between the outer part ( 6 ) and the inner part ( 8 ). The spring biases the inner part ( 8 ) against the sealing surface ( 16 ) on the tank stub ( 1 ).

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of German patent application no. 10 2009 036 373.4, filed Aug. 6, 2009, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a closing device for a vessel for an operating medium, in particular, in hand-held work apparatus.

BACKGROUND OF THE INVENTION

DE 295 19 299 U1 discloses a tank closure, which includes a tank closure device with a neck extending concentrically to its longitudinal axis and an external thread thereon. The tank closure device has a cover section having a flange surface, on which a sealing washer rests. The sealing washer is of an elastic, rubber-like material and serves to attach at the front edge of a tank stub of the fuel tank. A ring is arranged on the outer circumference of the cover section, which axially overlaps with the sealing washer and thus prevents the sealing washer from being squeezed out sideways or in the radial direction during tensioning with too much force.

DE 10 2007 043 991 A1 discloses a tank lid having an outer part and an inner part, which can be moved relative to each other in at least a limited rotation angle. In the outer part, a bottom part is also held which has an inner thread via which the tank closure can be screwed onto the tank stub. To seal the tank stub, the tank cover is screwed onto the fill stub, by means of which the sealing ring held between the inner part and the bottom part is charged in the radial direction and is thereby pressed against the outer circumference of the tank stub.

DE 20 2005 004 197 U1 discloses an integrated pressure control valve/vacuum valve, wherein the tank closure has two parts which are rotatable relative to each other and have a latching device. To close the tank opening, the tank closure is inserted into the tank stub. Radial protrusions for engaging with the tank stub are provided and formed so that by insertion of the tank closure into the tank stub, an engagement in the form of, for example, a bayonet coupling occurs. The latching device is provided to limit the force applied to screw closed the tank closure.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a closure device for a vessel for an operating medium, which has a simple construction and wherein the contact pressing force of the sealing surfaces is defined.

The closure device of the invention is for a vessel for holding an operating medium. The closure device includes: a tank closure having an inner part and an outer part; a tank stub defining a fill opening and a sealing surface surrounding the fill opening; the inner part and the outer part being limitedly movable toward each other in the axial direction of the tank stub; the inner part being rotatably fixed but axially displaceably guided on the tank stub; the outer part being rotatable relative to the inner part so as to be fix-tightly screwable on the tank stub; and, a spring arranged between the inner part and the outer part, so as to bias the inner part against the sealing surface of the tank stub.

The closure device according to an embodiment of the invention provides a tank closure with an axial seal, with only axial forces being applied to this seal, independently of the screw-on movement of the tank closure. Thereby, by decoupling of the outer part and the inner part in axial direction a defined contact force is given via the spring element. Furthermore, the closure device is subject to little wear, since the sealing surfaces are charged only in the axial direction and do not rub against each other.

According to a preferred embodiment of the invention there is at least one slot arranged in the tank stub, which slot runs in the longitudinal direction thereof. At least one radial projection is arranged on the inner part, and the projection is slidably guided in the slot. By taking this measure, an exclusively axial displacement of the inner part independent of the rotational movement of the outer part is achieved in a simple manner. It is seen as especially advantageous that the radial projection is formed as a rib in the longitudinal direction of the inner part, the width of the rib being smaller than the width of the slot. Due to the smaller size of the rib width, there is sufficient play to displace the inner part in the tank stub as resistance-free as possible. The configuration of the rib ensures the axial alignment, so that tilting is avoided. A conical entry is preferably arranged at the end of the slot adjacent to the fill opening to simplify the insertion of the rib into the slot. Furthermore, it is seen as advantageous that four grooves are evenly spaced in the tank stub on the perimeter and that two diametrically arranged ribs are provided on the inner part. In this way, for the insertion of the inner part into the tank stub, a rotation angle of <90° is sufficient to align the ribs relative to the slots.

In a further embodiment of the invention, at least one arm running in the longitudinal direction of the tank stub is arranged inside the outer part, which arm extends through the opening of the inner part and has a latching hook engaging behind a shoulder of the inner part. In this manner, the displacement path between the inner part and the outer part is limited in the direction of disengagement of the two parts. Thereby, the inner part and outer part are captively secured to each other. Advantageously, the radial surface surrounding the fill opening on the tank stub is formed as a sealing surface. Accordingly, a flange is integrally formed onto the end of the inner part adjacent the outer part, which is movable against the radial surface on the tank stub. Although a sufficient sealing effect can be achieved by a choice of materials and/or configuration of the sealing surfaces, it is, however, preferred that a sealing ring, which can be pressed against the radial surface of the tank stub, is arranged on the flange.

So that the outer part of the tank closure can be screwed onto the tank stub, the tank stub advantageously has a neck portion on which an outer thread is provided. The outer part preferably has an axial section, which surrounds the neck portion and has projections directed radially inwardly, which engage with the outer thread on the neck portion. The projections are advantageously formed by three noses, which include inclined top and/or bottom edges corresponding to the thread pitch.

In a further embodiment, a flange is arranged on the tank stub in such a manner that the axial section comes close to the flange when the tank closure device is fully attached. As a result of this measure, the thread region and the interior of the tank closure device are closed to the exterior, so that the penetration of dust or dirt particles into the outer part and especially to the sealing surfaces is avoided.

In an advantageous embodiment, the inner part is configured as a hollow body, which is closed by a base on the side facing away from the outer part. It is practical to provide a guide part substantially accommodated in the hollow body of the inner part, which, on the one hand, rests against the outer part and, on the other hand, is supported on the base of the inner part via a spring element. Due to the design of the inner part as a hollow body, the guide part can be accommodated in a space-saving manner and, because of the guide part, a tilting of the outer part and inner part is avoided. It is additionally advantageous that the guide part includes a centrical opening running in the longitudinal direction and a centrical pilot lug is arranged on the base, on which the guide part is mounted so as to be slidably displaceable. The spring element is preferably a helical compression spring which is supported on a radial collar of the guide part. The helical compression spring surrounds the guide part and the pilot lug.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings wherein:

FIG. 1 is a perspective view of a tank closure on a tank stub;

FIG. 2 is a view of the tank stub with a tank closure in the direction of arrow II of FIG. 1;

FIG. 3 is a section view along line of FIG. 2;

FIG. 4 is a perspective view of an exterior view of the tank closure of FIG. 3;

FIG. 5 is an exploded view of the tank closure and the tank stub in section along line V-V of FIG. 2;

FIG. 6 is a side view of the inner part of the tank closure;

FIG. 7 is a view along arrow VII of FIG. 6;

FIG. 8 is an alternative embodiment of FIG. 3;

FIG. 9 is a perspective view of the inner part of FIG. 8;

FIG. 10 is a view of the bottom of the inner part according to FIG. 9; and,

FIG. 11 is a view of the outer periphery of the inner part of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 shows a tank stub 1 with a tank closure 2. Only the upper portion of the tank stub 1 is shown and the further course of the tank stub is indicated by broken lines. The tank stub 1 includes a neck section 3 and a flange 4 to which the further course of the tank stub connects. An outer thread 5 is arranged on the outer surface of the neck section 3. A projection 31 is arranged on the upper edge of the outer surface of the neck section adjacent to the lower end of the outer thread 5, which in the closing direction when screwing the tank closure 2 includes a ramp and, in the opening direction, includes an essentially right-angled flank referred to the course of the outer thread 5.

On the neck section 3 there is an outer part 6 of the tank closure 2. The outer part 6 is configured in a pot-shaped manner and surrounds the neck section 3 with an axial section 7. An inner part 8 of the tank closure 2 extends through the neck portion 3 and the flange 4, wherein the inner part 8 is cylindrical and includes axially running ribs 9 on the peripheral surface. Only one rib 9 is visible in FIG. 1, the other rib is arranged offset by 180° and is therefore disposed on the back side. As will be explained in greater detail hereafter, the ribs 9 aid the axial guidance of the inner part 8.

FIG. 2 shows a view of the tank stub 1 with the tank closure 2 in the direction of arrow II of FIG. 1. This shows that the axial section 7 of the outer part 6 has a slightly larger circumference than the flange 4. In the flange 4 there is a centric opening 10 over whose circumference there are four evenly distributed slots 11, which extend in the longitudinal direction of the neck section 3 shown in FIG. 1. In the opening 10 there is a cylindrical inner part 8 which includes the diametrically arranged ribs 9 on its circumference. So that the inner part 8 can be easily displaced in the tank stub 1, the width of the ribs 9 is smaller than the width of the slots 11.

Four slots 11 are distributed over the circumference and two ribs 9 are provided, so that for inserting the ribs 9 into the slots 11 when putting the tank closure 2 on the tank stub 1 a maximum rotation of <90° of the inner part 8 relative to the tank stub 1 is needed to insert the inner part 8. The inner part 8 has a base 12, from which a tubular section 14 and a centrally arranged hollow lug 13 extend.

FIG. 3 shows a section view along the line of FIG. 2. The further course of the tank stub 1 under the flange is shown with broken lines, as in FIG. 1. The opening 10, which begins in the flange 4 and extends to the upper end of the neck section 3, runs axially in the tank stub 1. The upper end of the neck section 3 is formed by a radial surface 16. The neck section 3 includes an outer thread 5 on its outer surface. The inner part 8 of the tank closure 2 is arranged in the opening 10. The inner part 8 includes a cylindrical hollow body 17 which projects through the neck section 3 and the flange 4. The base 12 of the inner part 8, from which the tubular section 14 extends further down, is provided in the area of the hollow body 17 underneath the flange 4. The hollow lug 13 is arranged on the underside of the base 12. A radial flange 18 is formed on the upper end of the hollow body 17 and lies against the radial surface 16 of the neck section 3. As will be explained in greater detail hereinafter, a seal ring can be provided between flange 18 and the radial surface 16.

The outer part 6 of the tank closure 2 surrounds the neck portion 3 with its axial section 7. On the inner side, the axial section 7 includes multiple radially inwardly facing noses or projections 19, which interact with the outer thread 5 of the neck section 3 in the sense of a threaded coupling. This refers to a non-self-tightening thread. Alternatively to the outer thread, bayonet ribs running in circumference direction can also be arranged, behind which the noses 19 arrive as a result of rotation of the outer part 6 and engage there. The outer thread is preferably multi-threaded while considering the number of noses 19 provided on the axial section 7. Arms 20 extending in axial direction are formed on the inner side of the outer part 6. On the free ends of the arms 20, latch hooks 21 are provided, which are radially directed outwardly and which engage behind a radial shoulder 22 on the inner periphery of the hollow body 17. A hollow guide part 23 having a centric opening 15 running in the longitudinal direction is arranged concentrically between the arms 20. The hollow guide part 23 includes a radial collar 24 and, on the one hand, is supported on the outer part 6 and, on the other hand, is guided in a slidably displaceable manner on a coaxial guide lug 25 formed on the base 12. A helical compression spring 26 is arranged between the base 12 and the radial collar 24, which biases the inner part 8 in the closing direction of the tank closure 2 and thereby presses the flange 18 against the radial surface 16 with defined force, so that the tank stub 1 is closed.

FIG. 4 shows a perspective view of the tank closure 2 fully screwed on the tank stub 1. This position corresponds to that shown in section in FIG. 3. In this position, the axial section 7 of the outer part 6 rests directly in front of the flange 4, whereby the penetration of dust or dirt particles into the outer part 6 and especially to the sealing surfaces—cf. radial surfaces 16 and the flange 18 of FIG. 3—is avoided.

FIG. 5 shows the tank closure 2 and the tank stub 1 in an exploded view, namely along the line V-V of FIG. 2. The tank stub 1 in the depicted portion includes the neck section 3 with the outer thread 5 as well as the flange 4. A fill opening 27 is formed on the upper end of the neck section 3, which is surrounded by the radial surface 16 formed on the end face of the tank stub 1. The slots 11 which run axially in the neck section 3 and the flange 4 are arranged on the inner walls of the tank stub 1. The end of the slots 11, which is situated in the area of the fill opening 27, is provided with a guide-in cone 28.

Above the tank stub 1, the inner part 8 is shown, which includes the hollow body 17 with base 12 and the hollow lug 13 formed thereon, the tubular section 14, and guide lugs 25. At the upper end of the hollow body 17 an opening 29 is formed, around which the flange 18 extends. On the bottom side of the flange 18, there is provided a flat sealing ring 30 which is pressed against the radial surface 16 by the flange 18 when the tank closure 2 is in the closed state on the tank stub 1. Ribs 9 are present on each side of the inner part 8, which in the embodiment shown extend over the entire length of the hollow body 17 and the tubular section 14. The shoulder 22 is arranged as a circumferential radial edge on the inner periphery of the hollow body 17 close to the opening 29.

The helical compression spring 26, whose diameter is smaller than the diameter of the radial collar 24 on the guide part 23, is shown above the inner part 8. The helical compression spring 26 along with the guide part 23 are inserted through the opening 29 and into the hollow body 17 of the inner part 8, in which connection the guide lug 25 is inserted into the opening 15 of the guide part 23. Subsequently, the outer part 6, shown in the top of FIG. 5, is connected to the inner part 8 in order to form the tank closure 2. For this purpose, the outer part 6 is pushed onto the inner part 8. The axial section 7 accommodates the flange 18 and the arms 20 extend through the opening 29 and into the hollow body 17. In doing so, the inner part 8 and the outer part 6 are inserted into one another until the latch hooks 21 engage on the arms 20 behind the shoulder 22.

The helical compression spring 26 which rests on the base 12 of the inner part 8 and on the radial collar 24 of the guide part 23 causes the guide part 23 to rest against the inner side of the outer part 6, as shown in FIG. 3. When the tank closure 2 is removed from the tank stub 1, the latch hooks 21 rest against the shoulder 22 and thereby limit the maximum expansion of the helical compression spring 26. The noses 19, which are formed on the inner periphery of the axial section 7 and which engage in the outer thread 5 on the neck section 3 during screwing on, serve to screw the tank closure 2 onto the tank stub 1, as can be seen in FIG. 3. The noses 19 latch behind the projection 31 shown in FIG. 1, when the tank closure device 2 is fully screwed on, and thereby they ensure that the tank closure 2 does not automatically disengage, for example, as a result of vibration, since it pertains to a non-self-tightening thread. Only when the outer part 6 is pressed down and is simultaneously rotated in the opening direction by the operator can the safeguard be overcome. Of course, other embodiments of the projection are possible, for example, with inclines on each side. The configuration as a non-self-tightening thread also causes that the force of the helical compression spring 26 presses the tank closure device 2 and the outer part 6 upward whenever the tank closure 2 is not fully screwed on and the noses 19 are not engaged behind the projection 31 (FIG. 1), so that it is noticeable to the operator that the tank stub 1 is open.

The invention is not limited to the type of non-self-tightening thread or bayonet coupling described herein, but rather a standard thread can be used as well. In the latter case, however, the advantage of reliable recognition that the tank closure is not fully closed is not given.

FIG. 6 shows a side view of the inner part 8 with ribs 9 running laterally in the axial direction on the hollow body 17 and the tubular section 14, which, in the embodiment shown, extend over the entire axial length of the inner part 8 up until the bottom side of the flange 18. Of course, it is also possible to have the ribs shorter.

In FIG. 7, a view in the direction of arrow VII of FIG. 6 is shown. Thus, the elements arranged concentrically on the base 12 of the inner part 8, namely the hollow lug 13 and the tubular section 14 as well as the radially outwardly extending flange 18 which is arranged on the other end of the inner part 8, can be seen. The diametrical ribs 9 are provided on the outer periphery of the inner part 8 underneath the flange 18.

FIG. 8 shows an alternative embodiment to that shown in FIG. 3, wherein the tank stub 1 which includes a neck section 3, a flange 4, and an outer thread 5 substantially corresponds to the embodiment shown in FIG. 3. An opening 40 beginning in the flange 4 extends in axial direction in the tank stub. Said opening extends up to the top end of the neck section 3. At the top end of the neck section 3 there is a radial surface 36 which serves as a sealing surface. Starting at the radial surface, at least two axial grooves 41 are arranged on a section 33, which are offset by 180°. Preferably, however, four grooves offset by 90° are provided. An inner part 38 of a tank closure device 32, which includes a cylindrical hollow body 37, which extends through the neck section 3 and the flange 4, is arranged in the opening 40. In the section of the hollow body 37 below the flange 4 a base 12 is provided in the inner part 38, below which the inner part 38 further extends in the form of a tubular section 44. On the bottom side of the base 12 there is also a hollow lug 13 as in FIG. 3.

FIG. 8 further shows that a radial flange 34 is formed on the upper end of the hollow body 37, whose outer periphery merges into an axial ring 35, as is made clear in FIG. 9. Two ribs 39 arranged offset by 180° are provided on the inner periphery of the ring 35, which are guided in the grooves 41 (see FIG. 8). A sealing ring 42 is arranged between the radial flange 34 and the sealing surface 36. An outer part 46 of the tank closure device 32 surrounds the neck section 3 with an axial section 47 in the same manner as was described in regards to FIG. 3. The means for the screw closure are the same, too. Further, the concentric arms 20, the hollow guide part 23, the guide lug 25, and the helical compression spring 26 correspond in construction and technical effect with those in FIG. 3. The same goes for those parts not individually listed here.

FIG. 9 shows a perspective view of the inner part 38, wherein the base 12 with the hollow lug 13 can be seen in the hollow body 37. At the top end of the hollow body 37 there are the formed-on elements, namely the radial flange 34, axial rings 35, and ribs 39.

FIG. 10 shows the inner part 38 in a view from the bottom, and FIG. 11 shows a view on the outer periphery of the inner part 38. The reference numerals coincide with those used for the same parts in FIG. 9.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims. 

What is claimed is:
 1. A closure device for a vessel for holding an operating medium, the closure device comprising: a tank closure having an inner part and an outer part; a tank stub defining a fill opening and a sealing surface surrounding said fill opening; said inner part and said outer part being limitedly movable toward each other in the axial direction of said tank stub; said inner part being rotatably fixed but axially displaceably guided on said tank stub; said outer part being rotatable relative to said inner part so as to be fix-tightly screwable on said tank stub; and, a spring arranged between said inner part and said outer part, so as to bias said inner part against said sealing surface of said tank stub.
 2. The closure device of claim 1, wherein said tank stub defines a longitudinal direction and has at least one slot running longitudinally in said direction and said inner part has at least one radial projection arranged thereon and displaceably guided in said slot.
 3. The closure device of claim 2, wherein said radial projection is configured as a rib in the longitudinal direction of said inner part; and, said rib has a width which is less than the width of said slot.
 4. The closure device of claim 2, wherein said slot has an end adjacent to said fill opening; and, said slot has a lead-in cone arranged at said end thereof.
 5. The closure device of claim 3, wherein said tank stub has four of said slots evenly spaced over the circumference of said tank stub; and, said inner part has two of said ribs arranged diametrically thereon.
 6. The closure device of claim 1, wherein said inner part has an opening formed therein and a shoulder formed thereon; said inner part has an interior and at least one arm arranged within said interior; and, said arm runs in the longitudinal direction of said tank stub and extends through said opening and has a latch hook latching behind said shoulder.
 7. The closure device of claim 1, wherein said slots are arranged inside on said tank stub.
 8. The closure device of claim 1, wherein said slots are arranged outside on said tank stub.
 9. The closure device of claim 1, wherein said inner part has an end adjacent said outer part; said inner part has a flange formed thereon at said end thereof; and, said flange is movable toward said sealing surface of said tank stub.
 10. The closure device of claim 9, further comprising a sealing ring arranged on said flange; said sealing ring being configured to be pressable against said sealing surface; and, said sealing surface being a radial surface.
 11. The closure device of claim 1, wherein said outer part is configured to fix-tightly screw onto said tank stub via a non-self-tightening thread.
 12. The closure device of claim 1, wherein said outer part is configured to fix-tightly screw onto said tank stub via a bayonet coupling.
 13. The closure device of claim 11, wherein said tank stub has a neck portion having an outer thread formed thereon running in the peripheral direction.
 14. The closure device of claim 11, wherein said tank stub has a neck portion having at least one bayonet rib running in the peripheral direction.
 15. The closure device of claim 13, wherein said outer part has an axial section which surrounds said neck portion and said outer part has radially inward facing first projections for engaging said outer thread.
 16. The closure device of claim 15, wherein said projections are formed by three noses having upper and/or lower edges corresponding to the pitch of said thread.
 17. The closure device of claim 16, wherein said outer thread has an upper edge; a projection is arranged in said outer thread at said upper edge; and, at least one of said noses is configured to fully engage behind said projection in said outer thread when said outer part is fully screwed onto said tank stub.
 18. The closure device of claim 15, further comprising a flange arranged on said tank stub; and, said axial section coming close to said flange when said tank stub is fully attached.
 19. The closure device of claim 1, wherein said inner part is a hollow body having an end facing away from said outer part; and, said hollow body has a base on said end facing away from said outer part and said base closes off said hollow body.
 20. The closure device of claim 19, wherein said hollow body of said inner part has a guide part accommodated therein which, on the one hand, rests on said inner part and, on the other hand, is supported on said base of said inner part via said spring.
 21. The closure device of claim 20, wherein said inner part has a centric guide section arranged thereon; said guide part has a centric opening running in the longitudinal direction; and, said guide part is slideably displaceably journalled on said guide section.
 22. The closure device of claim 21, wherein said spring is a helical compression spring, which is supported by a radial collar of said guide part and surrounds said guide part and said guide section. 